1. Field of the Invention
This invention relates to switches, and more particularly to systems and methods for designing and implementing topologies for switch matrices.
2. Description of the Related Art
A relay is an electrical switch that opens and closes an electrically conductive path under the control of another electrical circuit. A switch matrix typically includes a plurality of relays used to selectively interconnect electrical paths for routing a signal. By opening and closing one or more relays within the switch matrix, a conductive path is created, thereby enabling a signal to be routed through the switch matrix. For example, a particular set of relays may be closed to connect a given input to a given output of the switch matrix. Switching is often implemented in test and measurement systems to automate routing of signals from one device to another. For example, a measurement device (e.g., voltmeter) may be coupled to an output of a switch having a plurality of inputs each coupled to a respective device under test (DUT). During operation, the measurement device may be used to take measurements from each of the DUT's by sequentially closing sets of relays, one after the other, to sequentially connect the inputs of the switch to outputs for each of the DUTs. Accordingly, switches may provide for simplified wiring, such that a test system can easily and dynamically modify internal connection paths without external manual intervention (e.g., without a user having to physically reroute cabling between devices). Similar switching techniques may be used in various operations that require dynamic routing of signals between devices.
Unfortunately, as the size of a switch matrix increases (e.g., the number of inputs and outputs increases), the number of relays may be increase to provide the desired connectivity. For example, an 8×8 cross-point matrix (e.g., a matrix having eight inputs and eight outputs) may employ one-hundred twenty-eight relays (e.g., of 1-Form-C type) to provide connectivity between each of the inputs and outputs. Increasing the number of relays may add to complexity and cost of the switching system. Moreover, conductive paths within relays can disrupt signals transmitted through the switch. For example, in the case of routing radio-frequency (RF) signals through a switch, dead-end paths (“stubs”) may form a capacitive load that result in reflections, thereby creating interference (e.g., reflections) that degrades the signal. In some instances, signal performance may be degraded simply by routing of the signal through the relays. For example, a relatively “stub-less” design may have degraded signal performance due to an increasing number of relays within the signal paths. Further, the complexity of the switch may increase complexity with regard to modeling the switch for the determination of how to efficiently route signals through the switch. For example, with an increasing number of inputs and outputs, it may be difficult to model the increasing number of valid routing scenarios.
Accordingly, it is desirable to provide a simple and effective systems and method for designing and implementing topologies for switching.